Abstract: In a power steering system for a marine vehicle having a propulsion unit and an operator actuatable steering helm, a power steering assist apparatus including a hydraulic fluid cylinder-piston assembly and actuated in response to steering actuation at the steering helm, and controls for maintaining anti-feed back upon a failure in the fluid source including a valve to establish fluid communication between a fluid source for the cylinder-piston assembly and the chamber in the assembly to either side of the piston thereby maintaining the chamber substantially full of hydraulic fluid during steering to effect movement of the piston upon steering actuation.

Abstract: A power steering assist system, especially adaptable for a marine vehicle having a propulsion unit pivotal about a steering axis and including a steering member to effect steering movement thereof about the steering axis and an operator actuable steering helm, comprising a hydraulic cylinder, a rotary valve body disposed adjacent the hydraulic cylinder and having a valve control adapted to establish fluid communication between the hydraulic cylinder and a fluid source for supplying hydraulic fluid to the cylinder. A ball screw, operably connected with the valve body, and a ball nut, having a recirculating ball connection with the ball screw, is operably connected to the piston so as to move axially on reciprocal movement of the piston. Pressurized hydraulic fluid is supplied to the cylinder and to either side of the piston to effect reciprocal movement of the piston, whereby axial movement of the ball nut is translated into rotary movement of the ball screw so as to rotate the valve body.

Abstract: The invention is to a power steering system for a marine vehicle having an operator actuable steering helm and a propulsion unit, including a steering arm, to effect steering movement thereof about a steering axis. The system is interposed between the steering helm and the propulsion unit and mounted remote from the propulsion unit, and further is hydraulically actuated in response to operative movement at the steering helm. A gear drive means, actuated in response to steering actuation at the helm, is operably connected to power steering assist means, comprising a hydraulic cylinder-piston assembly and hydraulic fluid source. Actuating means for regulating the flow of hydraulic fluid through the power steering assist means is operably connected to the gear drive means. An actuable output means, preferably a gear output means is operably connected to the power steering assist means for operative movement in response to the actuating means.